[GHC] #9660: unnecessary indirect jump when returning a case scrutinee

[GHC]

#9660: unnecessary indirect jump when returning a case scrutinee
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              Reporter:  rwbarton    |            Owner:
                  Type:  bug         |           Status:  new
              Priority:  normal      |        Milestone:
             Component:  Compiler    |          Version:  7.8.3
  (CodeGen)                          |         Keywords:
            Resolution:              |     Architecture:  Unknown/Multiple
      Operating System:              |       Difficulty:  Unknown
  Unknown/Multiple                   |       Blocked By:
       Type of failure:  Runtime     |  Related Tickets:
  performance bug                    |
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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Comment (by rwbarton):

 Well, initial results are somewhat inconclusive:

 {{{
             Min          -0.1%     -0.1%     -6.3%     -6.2%     -7.4%
             Max          +0.1%     +0.0%     +7.5%     +7.5%     +3.6%
  Geometric Mean          -0.0%     -0.0%     -0.2%     -0.2%     -0.0%
 }}}

 I believe the large variations are due to the same kind of issues I
 encountered in #8279. Got sucked into investigating that for a while, with
 no real progress.

 Anyways it seems like it ought to be a clear win; what's the best way to
 implement this for real?

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9660#comment:4>
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